Method of forming or truing up the peripheries of grinding wheels



Dcas 26,, 11922, 11 4410338 E. BUSWELL. METHOD OF Fonmmis OR Tnums UFTHEPERIPHERIES OF GRINDING WHEELS.

FILED MAR. 4, I919- Patented Dec. 2%, 1922 warren stares ll,4d,333 @ZXTENT @FFEQE EDWIN BU'SWELL, @F BIRMINGHAM, ENGLAND.

METHOD 01E FORMING 0R TRUING U]? "lHE PERIPHERIES OF GRINDING- WHEELS.

Application filed. March 4, 191.9. Serial 1V0. 280,558.

T 0 all whom it may concern:

Be it known that l, EDWIN BUswELL, a subject of the King of GreatBritain, and residing at Birmingham, in the county of Warwick. England,have invented certain new and useful Improvements in Methods of Formingor Truing Up the Peripheries of Grinding Wheels, whereof the followingis a specification.

According to this invention, the grinding surface of a grinding wheel ofa type which is made of carborundum, or other hard abrading material,bonded by a medium which is capable of change of form under pressure, isformed by pressing against the periphery of such Wheel a tool surfacewhich is shaped to the reverse of the required grinding surface, thegrinding wheel rolling against such surface of the tool. The char-.acter of the material of the grinding wheel ensures that the surfacethereof which is pressed against by the tool will change to a.

shape corresponding to the shape of the bearing surface of the tool, butowing to slight resilience of the material of the grinding wheel theshape of the surface of this wheel which has been pressed against by thetool will not be the identical counterpart of the corresponding surfaceof the tool, and this must be allowed for in preparing such surface ofthe tool. The tool can be used also for truing up the grinding wheelafter the same has become worn.

The invention is more particularly described with reference to thedrawings herewith, of which Figure 1 shows in elevation a forming toolapplied to the periphery of a grinding wheel in accordance with thisinvention, the

View being taken as looking towards one side of the forming tool andgrinding wheel, and showing the means by which the forming tool may bepressed towards the periphery of the grinding wheel and moved backtherefrom.

Figure 2 is an enlarged edge view of the ijffupper portion of a formingtool which is i-adapted to wheel to the sectional shape suited forgrindform the edge of'the grinding ing the root of a screw-thread.

igure 3 is a corresponding view to Figure 2, but shows the periphery ofthe forming tool to be of a sectional shape for forming the periphery ofthe grinding wheel to the sectional shape required for grinding thecrest of a screw-thread.

the front of the Figure 4 is a plan view of an application of theinvention "in which the forming tool Figure 6 is an end view of theparts shown by Figure 5, with the poppet and back centre I shown byFigure 5 omitted.

Referring first to Figure 1, A is a grinding wheel, and B a revolvingtool or spin-- ning wheel which is used to give the required sectionalshape to the periphery of the grinding wheel. C is a lever, the lowerend of which is pivotally connected with a fixed support D and the upperend of which is formed with a handle 0. A block C projects from theforward face ofthe lever, and a vertical slider E may be slidden intoany desired position vertically within guides at block C and then beclamped tightly to the block, such as lg a screw 0. The lower end of theslider is formed with a pair of jaws 6 between which is mounted thespinning wheel B. The grinding wheel A revolves in a suitable grindinglathe, and the spinning wheel B is brought up against the periphery ofthe grinding wheel by moving the lever C for wards towards the grindingwheel.

In Figure 2 the periphery of the spinning wheel B is shown to be formedwith a groove 1), and this groove is of a shape in transverse section toform the periphery of the grinding wheel of the required V-shape forgrinding the root of a V-shaped thread, or the root and the slopes ofsuch a thread; and in Figure 3 the periphery of a spinning wheel isshown to have a V-shaped formation 5 which will form in the periphery ofa grinding wheel a if-shaped groove suitable for grinding the crest of aV-shaped thread. As above indicated, however, the slight resilience ofthe material of the grinding wheel must be allowed for in shaping theperiphery of the forming wheel.

Referring now to Figure 4, A. is the grinding wheel, and B a spinningwheel the P67 ripheryi of which is formed as a spiral thread of whichthe section of the space between the spirals is such as to give to theperiphery of the grinding wheel the required sectional shape forgrinding out the root, or the slopes and root, of the screw thread whichit is required to grind. The grinding wheel A may be driven in a "lathe"and drag round the spinning wheel B, but, preferably, thespinwheel.

ning wheel is itself driven and drags round the grinding Wheel, and ineither case the grinding wheel or, preferably, the spinning wheel, isautomatically moved endwise so as to ensure that the thread of thespinning wheel will constantly maintain the same relation to theperipheryv of thegrinding wheel, that is to say, either the grindingwheel or the spinning wheel will move endwise the pitch of the threadfor each revolutionof the spinning wheel; and, of course, there must bemaintained sufiicient pressure between the grinding and spinning wheelsto ensure that the periphery of the grinding wheel will fill into thespace between the co' s of the thread. This last-mentioned r uirementismost conveniently accomplished by mounting the spinning wheel in acarriage which is movabl towards the grinding It will be obvious thatthe thread of the spinning Wheel may be formed and utilized in pressinginto the periphery of the grinding wheel to form a groove therein of thebearin a section which will adapt it to grind the crest of ascrew-thread, instead of the root, or slopes and root, of ascrew-thread. By

formin the operative surface of the spinning W eel as a spiral the wheelmay be made ofquite smalldiameter and yet pro- .'vide 'an'operativesurface running therearound which is as long or longer than the entirecircuit of the perlphery of the grinding wheel, thereby combiningtheadvantage of a wheel of small diameter, in respect of against theperiphery of the grinding w ee with the advantage, in respect of wear,of a wheel of large diameter of which the length of the circumference isnot less than that of the circumference of the grinding wheel. Thespiral around gthe spinning wheel Bmay commence at one end slightly lessthan its full size in section or diameter and gradually increase to itsfull size or diameter towards the other end, whereby the formation ofthe periphery of the grinding wheel is efi'ected more gradually thanwould otherwise be the case; but if thus formed there should be asufficient length of yes it of full formation to act against theperiphery of the grinding wheel throughout not less than an entirerevolution of such wheel.

Referring now to Figures 5 and 6, A is the grinding wheel, which isshown in position grinding through between two of the teeth of a pinionF. The pinion is fixed upon a mandrel B within the surface of which, andrunning lengthwise thereof-,are sunk a number ofparallel grooves 7,which are pitched apart exactly as are the spaces between the teeth ofthe pinion and are, respectively, in

alignment with such spaces and are each of a, transverse section which,if the periphery of the grinding wheel is rolled along therein. willform such periphery to thelshape required for grinding out metal frombetween two of the teeth of the pinion. The mandrel and pinion may betogether moved endwise to engage one of the grooves f of the mandrelwith the periphery of the grinding wheel and-cause such wheel to rollalong the groove while the grinding wheel is pressed against the mandrelor the mandrel is pressed against the grinding wheel. The grinding wheelis shown by a broken circle Figure 5, as having entered some distancealong one of the grooves After the periphery of the grinding wheel hasbeen truly formed by one of the grooves f, it may be moved into positionin which it is clear of such groove and of the pinion, and then themandrel and pinion may be turned an angular distance corresponding to acommon pitch of the pinion teeth and the grooves f, to enable thegrinding wheel to grind through another space between teeth and to betrued up by the groove f which will be in alignment with such space, andso on for all the remaining spaces between teeth of the pinion. Themandrel must, of course, be of such length as to allow the wholeperiphery of the grinding wheel to be trulyformed as it rolls along agroove 7, and-conveniently the mandrel is travelled axially to cause thegrinding wheel to roll along a groove. T'he mandrel maycarry-a number ofpmions which have the same diameter and pitch of teeth; and the form ofthe invention described with reference to Figures 5 and 6 may be appliedto forming or truing up grinding wheels for grinding articles of ananalogous character to pinions.

It willnow be obvious that a length of mandrel or bar having a singleforming sur- Having fully described my invention, wha

I claim and desire to secure by Letters Patent, is

1. The method of forming or truing upafter wear the periphery of agrinding wheel of which the substance consists of hard abradingmaterial, bonded by a medium which is capable of change of form underpressure, according to which the said pe-- riphery is caused to rollunder pressure against a prepared surface which is substantially thereverse in .cross section of the required periphery of the grindingwheel.

2. A method of forming or truing up after wear the periphery of agrinding wheel which is to be used for grinding; a screwthread and ofwhich the substance consists of hard abrading material bonded by amedium which is capable of change of 5 form under pressure according towhich the said periphery is caused to roll under pressure against aspinning wheel which has a spiral periphery of the pitch of the threadto be ground and formed as a reverse in 10 cross section of theperiphery of the grinding wheel, said spinning wheel during the rollingoperation being caused to move axially in relation to the grindingwheel.

In witness whereof I have hereunto signed my name this 12th day ofFebruary 1919, 15 in the presence of two subscribing witnesses.

EDWIN BUSWELL. Witnesses:

SYDNEY J. YOUNG, KATHLEEN M. THOMPSON.

